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LDEV-5953 Use ThreadLocal buffer pools for IOUtil #2722

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Merged
zspitzer merged 1 commit into from
Jan 2, 2026
Merged

LDEV-5953 Use ThreadLocal buffer pools for IOUtil #2722

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47 changes: 24 additions & 23 deletions core/src/main/java/lucee/commons/io/IOUtil.java
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Original file line number Diff line number Diff line change
Expand Up @@ -37,11 +37,7 @@
import java.io.UnsupportedEncodingException;
import java.io.Writer;
import java.net.URL;
import java.nio.ByteBuffer;
import java.nio.channels.Channels;
import java.nio.channels.FileChannel;
import java.nio.channels.ReadableByteChannel;
import java.nio.channels.WritableByteChannel;
import java.nio.charset.Charset;
import java.nio.file.Files;
import java.nio.file.Path;
Expand Down Expand Up @@ -71,6 +67,10 @@ public final class IOUtil {

private static final int DEFAULT_BLOCK_SIZE = 0xffff;// 65535

// ThreadLocal buffer pools to avoid repeated allocations in hot paths
private static final ThreadLocal<byte[]> BYTE_ARRAY_POOL = ThreadLocal.withInitial( () -> new byte[DEFAULT_BLOCK_SIZE] );
private static final ThreadLocal<char[]> CHAR_BUFFER_POOL = ThreadLocal.withInitial( () -> new char[DEFAULT_BLOCK_SIZE] );

/**
* copy an inputstream to an outputstream
*
Expand Down Expand Up @@ -326,24 +326,18 @@ public static final void copy(InputStream in, OutputStream out, int offset, int
* @throws IOException If an I/O error occurs during the copy operation.
*/
private static final void copy(InputStream in, OutputStream out, int blockSize) throws IOException {
// Creating channels from the input and output streams
ReadableByteChannel sourceChannel = Channels.newChannel(in);
WritableByteChannel destChannel = Channels.newChannel(out);

// Allocate a ByteBuffer of the given block size
ByteBuffer buffer = ByteBuffer.allocate(blockSize);

// Read from the source channel into the buffer, and then write from the buffer to the destination
// channel
while (sourceChannel.read(buffer) != -1) {
// Flip the buffer to prepare for writing
buffer.flip();

// Write to the destination channel
destChannel.write(buffer);
// Use pooled buffer for default block size, otherwise allocate
byte[] buffer;
if ( blockSize == DEFAULT_BLOCK_SIZE ) {
buffer = BYTE_ARRAY_POOL.get();
}
else {
buffer = new byte[blockSize];
}

// Clear the buffer for the next read
buffer.clear();
int len;
while ( ( len = in.read( buffer ) ) != -1 ) {
out.write( buffer, 0, len );
}
}

Expand All @@ -356,7 +350,7 @@ private static final void copy(InputStream in, OutputStream out, int blockSize)
* @throws IOException
*/
public static final boolean copyMax(InputStream in, OutputStream out, long max) throws IOException {
byte[] buffer = new byte[DEFAULT_BLOCK_SIZE];
byte[] buffer = BYTE_ARRAY_POOL.get();
int len;
long total = 0;
while ((len = in.read(buffer)) != -1) {
Expand Down Expand Up @@ -418,7 +412,14 @@ public static final void copy(Reader reader, Writer writer, boolean closeReader,
*/
private static final void copy(Reader r, Writer w, int blockSize, long timeout) throws IOException {
if (timeout < 1) {
char[] buffer = new char[blockSize];
// Use pooled buffer for default block size, otherwise allocate
char[] buffer;
if ( blockSize == DEFAULT_BLOCK_SIZE ) {
buffer = CHAR_BUFFER_POOL.get();
}
else {
buffer = new char[blockSize];
}
int len;

while ((len = r.read(buffer)) != -1)
Expand Down